To test FUSE with xfstests¹:
copy the mount.fuse.passthrough file into /sbin and edit the PASSTHROUGH_PATH, SCRATCH_SOURCE and TEST_SOURCE variables as needed.
Make sure that the SCRATCH_SOURCE and TEST_SOURCE directories exist.
Copy local.config into your xfstests directory
Tests can then be run with e.g.:
# make # sudo ./check -fuse -b
¹https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/about/